Thoughts about ipv6 white listing

[George Bonser]

> > Also, it might be that the recursive DNS server they are using over
> > IPv4
> > transport has IPv6 connectivity. As such the DNS request comes in
> over
> > IPv6 while the end user was using IPv4.
> 
> Then the end user would not have requested an AAAA record, it would
> have requested an A record.  If the client had no IPv6 it will not
> request an AAAA record.  If a request comes in on v6 for an A record,
> they will get the A record.

To clarify ... a request arriving on v6 can get an A or an AAAA record.

A request arriving on v4 will get only an A record.

Clients on v4 with a v6 dns server will show up asking for an A record over v6.  That request will be answered if there is an A record for the resource.

Clients on v6 with a v4 dns server will show up on v4 asking for an AAAA record.  That request will receive NOERROR and will fall back to v4

Clients on v6 with a v6 DNS server where the server can reach me but the client cannot reach me need to break so the problem can be fixed.